Fastening insulator for transmission lines



May 21, 1963 J. P. MAHANEY FASTENING INSULATOR FOR TRANSMISSION LINES 2 Sheets-Sheet 1 Filed Nov. 5. 1960 v INVENTOR.

John P. MAHRNEY BY y 21, 1963 J. R MAHANEY 3,090,827

FASTENING INSULATOR FOR TRANSMISSION LINES Mill Filed Nov. 4. 1960 2 Sheets-Sheet 2 INVENTOR. JOHN P MAHANEY AT TO EZM EY United tates Patent Ofiice 3,090,827 Patented May 21, 1963 3,090,827 FASTENING INSULATOR FOR TRANSMISSION LINES John Philip Mahaney, Blacksburg, Va., assignor to Virginia Plastics Company, Roanoke, Va., a corporation of Virginia Filed Nov. 4, 1960, Ser. No. 67,250 13 Claims. ((31. 174-172) This invention relates to insulating anchorages for electrical transmission lines, and in particular to insulating units which include clamping means for the conducting wire or cable.

An overhead transmission line is strung from pole to pole in a system of fixed catenaries, which entails securing of .the line at each pole against longitudinal movement. This arrangement, while permitting sidewise or swinging movement due to windage, prevents sliding movement of the conductor in its mounting which would result not only in wear and early failure but also in disarrangement and distortion of the catenary loops. It was early recognized that winding the conductor about the insulator or other manipulation of the conductor per se to achieve anchorage at the insulator was unsatisfactory from several standpoints, including excess labor and material as well as the problem of durability, and in lieu thereof, clamp means have been utilized. The present invention is concerned with such a clamp means, and provides an improvement whereby not only is the holding power substantially increased without departing from simplicity of structure, but stringing of the line from a position on the ground is greatly facilitated in a feature resident in the clamp means itself.

Briefly described the invention comprises a lever-operated over center clamp means with a clamp loop cooperating with a channel in the insulator, and with the operating lever having a notch for initial reception of the conductor, a notch for engagement by a manipulating tool to swing the lever into position where the conductor falls -unerringly into the channel, and a notch for engaging the lever to lower it to clamping position.

It is therefore an object of the invention to improve the holding power of clamping devices for transmission lines while maintaining simplicity of structure, low cost and ease of manufacture.

Another object is to facilitate homing of the transmission line into its anchorage in a ground operation, and a particular object is to combine the latter result with the former in a dual purpose clamp structure.

A further and particular object is to improve clamping eificiency by engagement of the conductor along a tortuous path without reduction in mechanical strength or waste of material.

These and other ends, which will be apparent to those skilled in the art, are attained by the present invention, a preferred form of which is described in the following specification, and illustrated in the drawings, in which:

FIGURE 1 is a view in perspective of the insulating conductor anchorage secured to the cross arm of a telephone pole, with the clamp in locked position and the wire preliminarily strung on the clamp lever,

FIGURE 2 is a view similar to FIGURE 1 showing the clamp in open position and the wire deposited into the notch in the insulator,

FIGURE 3 is a perspective view of the insulator, enlarged, showing the wire clamped in place,

FIGURE 4 is a sectional view through the insulator taken on the plane of the line 4-4 of FIGURE 3,

FIGURE 5 is a rear elevational view of the insulator, as seen along the line 55 of FIGURE 4,

FIGURE 6 is a front elevational view of the insulator of FIGURE 4, as seen from the right of that FIGURE,

FIGURE 7 is a side elevational view of the insulator of FIGURE 6, as seen along the line 7-7 of that FIGURE, and

FIGURE 8 is a fragmentary, exploded view, in perspective, of the trunnion mounting of the operating lever of the clamp.

Referring to the drawings by characters of reference, there is shown, in FIGURES 1 and 2, a cross arm 10 of a telephone pole, from which depends a J bolt 12, on the upturned end of which is threadedly secured a line-supporting unit 14 of plastic or other suitable insulating material of proper mechanical strength.

The material, for instance, may be Delrin, a product of the Dupont Company, which is a good electrical insulating material, and relative to plastics generally, is rigid, with high mechanical strength, and resistant to cold ilow under pressure. Alternatively, any rigid, high strength insulating plastics with good weathering resistance, and resistance to cold flow would be suitable. Included in this class are polyesters, epoxies, polycarbonates, and nylon, including plain or glass-filled versions of these.

[As seen in FIGURE 4, the insulator is preferably wedgeshaped in profile for economy of material while comporting with proper design for stress distributions. For the same reasons, the body has a cavity 16 in its bottom which locates the mounting on the J bolt near the center of the body and reasonably close to the point of dwell of the line wire. The top of the body has a transverse notch 18 with upwardly convex bottom, and with sides disposed at an acute angle to provide a wedge-shaped trench constituting a repository for the line wire. The back wall 20 of the notch is substantially higher than the front wall 22 to provide a backstop which cooperates with the clamp lever in the mounting of the line wire, as will be detailed later.

The clamp unit is swingably mounted on a pair of trunnions 24, integral with and extending from the sides of body 14 near the bottom thereof. On these are mounted the radial arms 26 of a U-form rocking lever, the outer ends of the arms being connected by a cross member 28 of circular cross-section. As seen in FIGURE 8, trunnions 24 each rise from a boss 30 on the body 14 which acts as a bearing surface for hub elements 32 of arms 26. A yieldable lock means for holding the swing lever in clamping position is provided in a radially disposed ridge 34 rising from the bearing boss 30, and cooperating with a radially disposed channel 36 in the hub 32. The top of the ridge 34 is rounded or chamfered to enable notch 36 to ride onto or off the ridge, the arms 26 spreading slightly apart in the process due to their natural resiliency. A pin 38 protruding from the body 14 provides a positive stop for the lever 26 at or just beyond the clamping position thereof.

The contact device of the clamp element comprises a generally U-form loop of tough, spring wire having radial 3 arms 40 with dog-leg bends 4'2 and with outer ends bent transversely to provide horizontal arms 44 resiliently held in aligned, transverse bores in the respective arms 26 at points located a short radial distance outward from the axis of trunnions 24.

At each side of the body 14, the tops of arms 40' are looped, as at 46, to protrude forwardly of the notch 18, and the upper, transverse arm 48 of the spring clamp, extending between the loops 46, has a curvature paralleling that of the convex bottom of notch 18. It will be understood that the notch bottom may also have a degree of curvature as viewed perpendicular to a horizontal plane, in which case the span 48 will be formed to match.

The clamp span 48 is held at all times in position for cooperative movement with respect to the notch 18 by a guide means comprising a pair of wire tabs 50 secured near the upper ends of clamp arms 40 and bent into enclosing relation to the rear face of body 14. This keeps the clamp wire from swinging forward more than a small amount, and the clamp span 48 will abut the rear wall 20 of the notch to inhibit swinging in a rearward direction.

It will now be apparent that with the clamp in open position, as seen in FIGURE 2, downward swing of the lever arms 26 will draw span 48 of the spring clamp into the notch, and if a Wire 52 is in the notch it will be securely clamped in place. The efliciency of the clamping action Will depend, of course, on the loading characteristics of the spring clamp and the extent of its deformation. However, for'any given set of conditions in this category, the clamping will be improved by the length of the bottom of the notch and its curvature in either or both of the directions mentioned. Conversely, with a long and suitably curved notch, the spring pressure may be lessened and damage to the line wire minimized. With respect to wire damage and also to keep out atmospheric debris, the span of the spring clamp will preferably have an outer covering '54 of rubbery material. For proper clamping, the rest position of center tabs 44 of the spring clamp, as determined by the location of ridge 34 will be slightly over center.

To the extent thus far described the invention is completely operative, and with the attendant advantages enumerated, it being only necessary, operating from the ground or from an elevated position, to drop the line wire in the notch 18, with the clamp open, and then bear down on the lever bar 28, carrying the lever arms to locked position. However, in operating from the ground, the notch 18 presents a relatively small target, and this difficulty is complicated by the presence of the cross span of the spring clamp. Furthermore, prior to clamping, the line wire is not trapped in the notch and may be dislodged in preliminary, manipulatory adjustments, as for instance tension catenary adjustments.

Therefore, in order to facilitate mounting of the wire from the ground, as with a pike, and in order to cage or trap the line wire during adjustment certain elements are provided on the cross member 28 of the operating swing lever. As shown, these elements are embodied in a single, radially disposed element 55 on the member 28, integral therewith, constituting a grappling unit and comprising a curved tongue 56 (FIGURE 4) defining a slot 58 in which the wire is laid preliminary to swinging it into final position in notch 18. The ease with which this preliminary mounting may be accomplished will be readily apparent from an inspection of FIGURE 4, the front face of the body 14' providing an extensive, unobstructed and easily negotiated target from which the line wire may be unerringly lowered into notch 58. As best seen in FIGURE 7, the geometry of the parts is such that when lever bar 28 is swung to its extreme upper position the opening of notch 58 coincides with the opening of notch 18 and the line wire 52 not only drops into notch 18 but is trapped there, in loose condition while the lever remains in its upper position.

For operation from the ground, a pike 60 is employed, as shown in FIGURES -1 and 2. This comprises a handle of suitable length with a rod element protruding from one end which is bent into suitable shapes for the several functions contemplated. Thus, the working end has a central, trapezoidal loops 62, and a lateral, closed loop 64. Either loop may be used, internally or externally, for pushing or pulling, as the particular situation demands. For instance, the upper part of loop 64 may be employed as a hook to lift the line wire into the notch 58 (FIGURE 1). For lifting the clamp-operating lever, to simultaneously open the clamp and mount the line wire in the insulator notch, an arcuate notch 66 is provided in element 55. To start the clamp-opening movement, this notch is engaged by the large loop 62 of the pike and first pulled to a downwardly disposed position, after which it is pushed by the loop to the position shown in FIGURE 2. For closing the clamp, an arcuate notch 68 in unit 55 is engageable by a loop for pulling and pushing to the position shown in FIGURE 4. A stop 70 on unit 55, cooperating with the J bolt 12 may be employed in lieu of or as a standby, in addition to, stop pin 38.

Having thus described my invention, what I desire to claim by Letters Patent is as follows:

I claim:

1. A combined hanger and clamp for transmission lines comprising an insulator body of upwardly tapering wedge form having a recessed bottom with a central threaded bore, and having an upper portion notched in a generally wedge-form channel having a bottom with double curvature and a rear wall higher than the front Wall, a generally U-form lever swingably mounted in opposite faces of said body near the bottom thereof, a manipulating panel on said lever disposed transversely to the axis of swing thereof and having a first notch arranged at an acute angle to the radius of swing of the lever and adapted to mate with said channel in closing relation in One position of swing, a second notch spaced from said first notch and opening in the same general direction as said first notch, and a third notch spaced from said second notch an opening in an opposite direction from that of said second notch, a generally U-form spring clamp member mounted for swinging movement in said lever at points radially outward from the center of swing thereof, and having a central span engageable in and conforming to the shape of the bottom of said channel, and having forwardly extending loops at the ends of said channels, and guide tabs on said clamp member extending transversely of said body rearwardly of said rear wall of said channel, and yieldable detent means for holding said lever against swinging movement in the closed position of said clamp member.

2. A combined hanger and clamp for transmission lines comprising an insulator body of upwardly tapering wedge form, and having an upper portion notched in a generally wedge-form channel having a bottom with double curvature and a rear wall higher than the front wall, a generally U-form lever swingably mounted in opposite faces of said body near the bottom thereof, a manipulating panel on said lever disposed transversely to the axis of swing thereof and having a first notch arranged at an acute angle to the radius of swing of the lever and adapted to mate with said channel in closing relation in one position of swing, a second notch spaced from said first notch and opening in the same general direction as said first notch, and a third notch spaced from said second notch and opening in an opposite direction from that of said second notch, a generally U-form spring clamp member mounted for swinging movement in said lever at points radially outward from the center of swing thereof, and. having a central span engageable in and conforming to the shape of the bottom of said channel, and having forwardly extending loops at the ends of said channel, and guide tabs on said clamp member extending along the rear face of said body rearwardly of said channel, and yieldable detent means for holding said lever against swinging movement in the closed position of said clamp member.

3. A combined hanger and clamp for transmission lines comprising an insulator body of upwardly tapering wedge form, and having an upper portion notched in a generally wedge form channel having a bottom with double curvature and a rear wall higher than the front wall, a generally U-form lever swingably mounted in opposite faces of said body near the bottom thereof, a manipulating panel on said lever disposed transversely to the axis of swing thereof and having a notch arranged at an acute angle to the radius of swing of the lever and adapted to mate with said channel in closing relation in one position of swing, a generally U-form spring clamp member mounted for swinging movement in said member on an axis radiall outward from the center of swing thereof, and having a central span engageable in and conforming to the shape of the bottom of said channel, and having forwardly extending loops at the ends of said channel, and guide tabs on said clamp member extending along the rear face of said body rearwardly of said channel, and yieldable detent means for holding said lever against swinging movement in the closed position of said clamp member.

4. A combined hanger and clamp for transmission lines comprising an insulator body of upwardly tapering wedge form, and having an upper portion notched in a generally wedge form channel having a bottom with double curvature and a rear wall higher than the front wall, a generally U-form lever swingably mounted in opposite faces of said body near the bottom thereof, a manipulating panel on said lever disposed transversely to the aXis of swing thereof and having a notch arrange-d at an acute angle to the radius of swing of the lever and adapted to mate with said channel in closing relation in one position of swing, a generally U-form spring clamp member mounted for swinging movement in said member on an axis radially outward from the center of swing thereof, and having a central span engageable in and conforming to the shape of the bottom of said channel, and having forwardly extending loops at the ends of said channel, and guide tabs on said clamp member extending along the rear face of said body rearwardly of said channel.

5. A combined hanger and clamp for transmission lines comprising an insulator body having an upper portion notched in a bottom with double curvature and a rear wall higher than the front wall, a generally U-form lever swingably mounted in opposite faces of said body near the bottom thereof, a manipulating panel on said lever disposed transversely to the axis of swing thereof and having a notch arranged at an acute angle to the radius of swing of the lever and adapted to mate with said channel in closing relation in one position of swing, a generally U-forrn spring clamp member mounted for swinging movement in said member on an axis radially outward from the center of swing thereof, and having a central span engageable in and conforming to the shape of the bottom of said channel, and having forwardly extending loops at the ends of said channel, and guide tabs on said clamp member extending along the rear face of said body rearwardly of said channel.

6. A combined hanger and clamp for transmission lines comprising an insulator body having an upper portion notched in a generally wedge form channel having a bottom with double curvature and a rear wall higher than the front wall, a generally U-forrn lever swingably mounted in opposite faces of said body near the bottom thereof, a finger on said lever disposed transversely to the axis of swing thereof and having a notch arranged at an acute angle to the radius of swing of the lever and adapted to mate with said channel in closing relation in one position of swing, a generally U-form spring clamp member mounted for swinging movement in said member on an axis radially outward from the center of swing thereof, and having a central span engageable in and conforming to the shape of the bottom of said channel, and means on said member cooperating with said body and constraining said central span to a path aligned with the depth of said channel.

7. A combination hanger and clamp for transmission lines comprising an insulator body having an upper portion notched in a generally wedge form channel having a rear wall higher than the front wall, a generally U-form lever swingably mounted in opposite faces of said body near the bottom thereof, a finger on said lever disposed transversely to the axis of swing thereof and having a notch arranged at an acute angle to the radius of swing of the lever and adapted to bridge the width of said channel in one position of swing, a generally U-form spring clamp member mounted for swinging movement in said member on an axis radially outward from the center of swing thereof, and having a central span engageable in said channel near the bottom thereof, and means on said member cooperating with said body and constraining said central span in a path leading into and out of said channel.

8. A combination hanger and clamp for transmission lines comprising an insulator body having a lateral notch in its top with a rear wall higher than the front wall, a generally U-form lever swingably mounted on said body for movement between a position adjacent said notch to a position downwardly of said body, said lever having a grappling unit with a slot opening generally upwardly in the down position of said lever, and opening generally downwardly and in spanning relation to said notch when the lever is in the upward position, an over-center spring clamp element swingably mounted on said lever, and guide means on said element cooperating with said body and constraining said element to a path leading into and out of said notch.

9. A combination hanger and clamp for transmission lines comprising an insulator body having a lateral notch in its top, a generally U-form lever swingably mounted on said body for movement between a position adjacent said notch to a position downwardly of said notch, said lever having a grappling extension with a slot opening generally upwardly in the down position of said lever, and opening generally downwardly and in spanning relation to said notch when the lever is in the upward position, an over-center spring clamp element eccentrically mounted for swinging movement on said lever, and guide means on said element cooperating with said body and constraining said element to a path leading into and out of said notch in said body.

10. A combination hanger and clamp for transmission lines comprising an insulator body having a lateral channel in its top with a rear wall higher than the front wall and a bottom having curvature in vertical and horizontal directions, an over-center clamp with an operating lever carried by said body and a spring wire eccentrical ly mounted on said lever, means to guide said spring wire into and out of said channel, and a grappling extension on said lever having a notch opening downwardly and spanning said channel in one position of said lever and opening upwardly in another position of said lever.

11. A combination hanger and clamp for transmission lines comprising an insulator body having a lateral channel in its top and a curvilinear bottom, an over-center clamp with an operating lever carried by said body and a spring wire eccentrically mounted on said lever, means to guide said spring wire into and out of said channel, and a grappling extension on said lever having a notch opening downwardly and spanning said channel in one position of said lever, and opening upwardly in another position of said lever.

12. A combination hanger and clamp for transmission lines comprising an insulator body having a lateral channel in its top, an over-center clamp with an operating lever carried by said body and a spring loop eccentrically mounted on said lever, means to guide said loop into and out of said channel and a grappling extension on said lever having a notch opening downwardly and spanning said channel in one position of said lever, and opening upwardly in another position of said lever.

13. A combination hanger and clamp for transmission lines comprising an insulator body having a lateral channel in its top, an over-center, clamp with a spring loop adapted to engage in said channel and an operating lever, and a grappling extension on said lever having a notch opening downwardly and spanning said channel in one position of said lever, and opening upwardly in another position of said lever.

References Cited in the fileof this. patent UNITED STATES PATENTS OBrien Aug. 17, Blackburn Aug. 29, Schonbury Feb. 27, Carter July 2, Friend Mar. 14, Parra Feb. 25, Balli'et Aug. 3, Ettin ger 'Feb. 29, Cook Oct. 23, Lucas June 27, Swearingen Feb. 16, 

13. A COMBINATION HANGER AND CLAMP FOR TRANSMISSION LINES COMPRISING AN INSULATOR BODY HAVING A LATERAL CHANNEL IN ITS TOP, AN OVER-CENTER CLAMP WITH A SPRING LOOP ADAPTED TO ENGAGE IN SAID CHANNEL AND AN OPERATING LEVER, AND A GRAPPLING EXTENSION ON SAID LEVER HAVING A NOTCH OPENING DOWNWARDLY AND SPANNING SAID CHANNEL IN ONE POSITION OF SAID LEVER, AND OPENING UPWARDLY IN ANOTHER POSITION OF SAID LEVER. 